The Greeks also identified Isis with Io, one of Zeus' affairs. The story went (in classical mythology) that to protect her from Hera's rath, Zeus tansformed Io into a cow, but Hera called his bluff and demanded the cow, who was then placed, by Hera, under the watch of 100-eyed Argus. Then Hermes, by Zeus' order, killed Argus, sprung the cow, and she travailed around the known-world trying to escape Hera. When she got to Egypt she is said to have recovered her human form.
Because the greeks identified Io with Aset, they called the goddess Io-is, Isis.